1. Field
The following description relates to an optical fiber containing a graphene oxide and a reduced graphene oxide, a gas sensor including the optical fiber, a method for manufacturing the optical fiber, and a method for manufacturing the gas sensor including the optical fiber.
2. Description of Related Art
Since an optical fiber has advantages in that it is less interfered by external environments and has low information loss rate, it has been widely used in various fields for common communication networks, cable broadcasting and transmission or detection of information of various automatic devices, and the application fields of the optical fiber gas sensor have been recently diversified. A sensor using an optical fiber accomplishes its detecting performance by using elasticity by a temperature or a pressure, a phase difference of light, the Doppler effect, or others. For example, being utilized for various purposes of temperature sensors, pressure sensors, gyroscopes, speedometers, wind vanes, gas leakage sensors, etc.
Among those sensors, sensors useful for detection of gases, compounds, bio-molecules and so on have been long spotlighted, and many research results thereof have been published. Especially, a gas sensor has been used in a wide range of fields such as chemistry, pharmaceuticals, environments, medicine, etc., and it is expected that there will be more researches on gas sensors in the future. In addition, as social demands for environment preservation, safety management, etc., are increasing, the performance and the specifications required for the gas sensor are also being highly advanced.
However, in general, the gas sensor is problematic in that its selectivity to a specific gas is low, and its sensitivity is deteriorated in high humidity and strong acid or base environments. Thus, many researches are concerned with trying to overcome such problems and develop gas sensors having superior selectivity. Typically, the effect of suppression of humidity is accomplished at a high temperature of 165° C. [Cantalini, C. et al. Sensitivity to NO2 and cross-sensitivity analysis to NH3, ethanol and humidity of carbon nanotubes thin film prepared by PECVD. Sens. Actuators, B 95, 195-202 (2003)].
Accordingly, achieving high sensitivity and selectivity under high humidity conditions and maintaining high sensitivity are most difficult in realizing an effective gas sensor. It would be difficult to enable a gas sensor to have selectivity for detecting existence of a particular gas of a media containing two or more different gases under normal atmospheric conditions. This detectability is possible by virtue of different adsorption properties and reactivity properties of analytes with respect to substance. One (1)-dimensional semiconducting metal oxide nanowires have been widely researched for detection of highly sensitive gases due to their high sensitivity to different types of gases. Recent researches have reported that bonding between nano-crystals/nano-particles within a graphene-based gas sensor can improve sensor performance in view of sensitivity/detection limit, response time, or recovery time. In addition, other groups have verified that a reduced graphene oxide (rGO) can function as a gas/vapor sensor resulting in favorable outcomes.